Spade connector convertible to ring connector



Oct. 9, 1951 Q. BERG SPADE CONNECTOR CONVERTIBLE TO RING CONNECTOR 2 Sheets-Sheet 1 Filed Feb. 8, 1949 Tlc'. F.

w M mr\/i lNVENTOR J- V A/T/A/ BERG,

7 MY W1 TTOR I" S i Oct. 9, 1951 Q. BERG 2,570,753

SPADE CONNECTOR CONVERTIBLE TO RING CONNECTOR Filed Feb. 8, 1949 2 Sheets-Sheet 2 I NV ENTO R qua/v77 552g.

ATTOR 5 Patented Oct. 9, 1?51 j; o TAT CONN'ECTOR CONVERTIBLE TO RING-CONNECTOR Quentin Berg, New. Cumberlanmyal,.assignor to Aircraft Marine'Pioduc'ts, Iiifc 7 Application February 8, 1949"; Serial NQ 15 ,183 ,1 .cn m,.j. c1. 1"'i3:269;

: f'lhisginvention relates to electrical terminals 2 air agrivet, or :the; shank. of a. screw or .bolt.; Among-these terminals are the spadexor. spade. tongue type having thespade-tongue forked to formtwo-parallel spade legswith an entry slot therebetween-. into which the;- male. terminal is received- This spade-tonguetype-of' terminal is; easily; attached.;.to. themale terminal by slipping. the spade-legs onto'the opposite sides of. the :male. terminal and thenstightening a; nui' gor screw, .or

i e so; as-t gc am t p e-t s e-a nzpor- @9 5: T us: ncma i m s li uc n qse ar-i tions spadeetongue terminals are usedwith. the; e entase that. th m e ermin may be i the form: of screws assembled .on to aterminal plate-,priorto. the wiring; operation-and then ,the

terminalsrare. slipped onto their respective screw shanks-and the screws-are. merely: tightenedup-,= However, ,difiiculties haverbeen; encountered. with; spade tongue terminals particularly becausenoi. theerelative ease of disconnection from the-male; terminal when; the tongue-clamping; pressure is. relie ed as: might occur undnvibratdry or impact conditions.

. For trample, with-householdl appliances zwhich are mass; produced and; which. are created. .-and.; shipped (to the-ultimate. consumer. for. installation: ba -inexperienced hands, the disconnection. of. a single te'rminalginay render the appliance inop,-;- era'tive and I. this may cause. a disproportionately large; Srvieexperise and may even damagethe goodwill. 'o'ffthe manufacturer;

. The: simple looseningj oithe clamping action.- ofia malelterminal. will not cause this-difli'culty it; theflspade-tongue terminal; is replacedaby. a; rii igi shapedliterminallhaving its..tongue formed; by'a flag; However, ring-tongue terminals are relatively:-unsatisfactory for... use in many operations-because. theymust he -slipped onto the end ofgthe. inale terminahv That is, whenithe malev terminalis a screw; thee-terminal must be held. on, the screw or over the. screw-hold while the; screw is startedl and: turned: into the hole; and; when the;.male-terminal isa bolt or .'stud,;; the ring-tongue must he; slipped over the bolt-prior: tclthe-startingz of. theanut ,or.v other clamping;deg Vice thereon.

. ject -is to provide, for. the manufacture of. ter ni- It an -.objectoi the present-invention to pro videg; an improved terminal, construction and modeofiapplying ;the same which avoid .the difiiculties encountered with similar terminals; in; the past. It is a primary objectof this: invention toe provide a; terminal-tongue construction which; has the -advantagesof the prior spade tongue atorminais :and also. the advantages of; the ring-tongueterminals. Another object of; the presentinvention zis that of providing improved tel-init als:v which- .may; be easily attached to maleterminalsv with;;a.simple unidirectional movementgand then are free ofgdangerrof accidental disconnection. A further obj ect* is; to 'PIOVidG'. a;

terminal oft the; above3character which will; not becomeldisconnected accidentally, and yet which;

may be disconnected when desirable- Another object .is .to provide forthe manufacture and use of terminals of the above character with maxi mum"efiiciencylandeconomye A stilliurther obnals in such a manner as to use a minimum amount ofisheet metaland require a minimum amount-pig workyin the 'Inanufacture as well as in:

the .-.attachment. of the terminals to their ma-le erm als:-

In: connections utilizing terminals of this gen Q eral character, including spade-tongue terminals and ring-tongue. terminals, the looseningof the clamping action associated with a male terminalg isaccompanied by an increase in the contact re:-

sistance between thetwo terminals, and withl'owvoltages the resistance may be of such mag ni tude thatfit produces the efiect of an open cir cuiteven though the-terminals are still physically connected. Further; under heavy current conditionssucha loose connection may become excessively hot even to the extent of melting and deforming the assemblies. It is a further: object of the present invention to overcome this difficulty; by preventing the loosening of the clamping action and also-by. maintaining arel:.

atively: low contact resistance even when the clampingaction is not entirely right. i v I Ring-tongue terminals have the advantage oi providing an annular zone. or area of contact substantiallythroughout the peripheryof the:

male terminal, 3 whereas spade-tongue terminals provide anarea of contact which is substantially less-than thatof the ring-tongue terminal. Fur;

thermorethis area of contact with spade-tongue terminalsris. quite variable depending upon the.

I In this specification and the accompanying 1 drawings, I have shown and described a preferred embodiment of my invention and various modifications thereof; it is to be understood that these are not intended to be exhaustive or limiting of the invention, but on the contrary are given principally for purpose of illustration in order that those skilled in the art may fully understand the invention and principles thereof and the manner of applying it in practical use so that they may modify and adapt it in various forms, each as may be best suited to the conditions of a particular use. v r

' In the drawings: Figure 1 is a perspective view of a terminal constituting one embodiment of the invention;

Figure 2 is-a top plan view of the terminal of Figure 1 prior to being crimped to a wire;

Figure 3 is a view similar to Figure 2; but showing the terminal crimped to a wire as in Figure 1' and after attachment to a male terminal; the male terminal and the flattened rufile portions are shown with dotted lines;

Figure 4 is a side elevation of the terminal as shown in Figure 3 prior to being clamped by a inale terminal member; ,1 Figure 5 is a sectional view on the line 5-5 of Figure 2;

Figure 6 is a top plan view on reduced scale of a strip of terminals of the type shownin Figures 1 to 4; and

Figures 7 and 8 are similar to Figures 2 and 3, but show another embodiment of the invention.

Referring particularly to Figure l of the drawing, crimped to the bared end I of an insulated wire 4 is a terminal 2, which has a spade-tongue shown generally as 5 bifurcated to form a pair of spade legs 8. Between legs 8 is a slot i2 which is adapted to receive a male terminal such as the shank of a screw. Each of legs 8 has an edge pleat-like rufile or fold [4, shown here as being located approximately centrally of its longitudinal extent (see Figure 2). These folds are shown oppositely disposed with respect to the longitudinal axis of the terminal that is, the axis parallel to the insulated wire 4 and the common central axes of the folds are on a line which crosses this longitudinal axis at a point l6, referring to Figure 2 which is nearer the mouth of slot l'2 than the normal position of the axis of a male terminal to which terminal 2 is to be connected. For example, the shank 18 of such a male terminal is indicated in broken lines and has an axis 20 which is positioned to the left of point 16. Each of legs 8 has an end segment 22 which is integrally connected to the base portion 5-of its legs with its fold l4, and a relatively narrow fiat portion 24 adjacent slot [2 at the junction of the 7 narrow edge at the peak l5 pf the fold from the i base I! of the fold integral with and of substantially the same thickness as the adjacent flat portions of its leg; this form is obtained by pressure forming or drawing the fold Hi from the flat spade legs 8. In use a terminal 2 is first crimped to the end of an insulated wire as in Figure 1 and its spade is then slipped onto a male terminal, illustratively at shank N3 of a screw which is positioned as indicated in Figures 2 through 4. The screw is then tightened with the head 26 of the screw (see Figure 4) engaging thepeaks l5 of folds i4 and with the bottom surface of the spade resting on a terminal plate 28. As the screw is tightened from the position shown in Figure .4, the folds I4 are flattened down toward the plane of the fiat portions of legs 8. During this flattening operation, the two triangular portions of each fold exert strong forces toward each j other; as their areas are greater than the area beneath them which they are driven to occupy,

and the reactions of these forces are resolved to effectively push th-eouter peripheral areas of the end segments 22 away from the base portion of the leg. Segments 22 therefore move toward each other with the narrow flat portions 24 acting'as pivot zones around which the segments. swing. Thus, the mouth of slot I2, is partially closed by these end segments 22 with the result that the shank N3 of the male terminal will no longer slip from the slot. 7

The pleat-like ruffles or folds l4 shown in the embodiment of Figures 1 through 6 are of the triangular plane type, and in fact, resemble somewhat one-half of a dimple.- When desirable, other types of folds or ruffles may be used to obtain the advantages of the present invention. The general characteristic of such folds or ruffles is that they have greater surface area at the outer margin of the-leg than at the inner margin, and therefore, when flattened by being isubjected to pressure they increase'the length of their respective legs at their outer periphery; this causes the leg to bend and wrap around themaleterminal located at the inner margin of the leg. For simplification, theterm ruffle is used herein as a generic expression for such folds orruffles.

In effect, the flattening of the rufiles causes each of the legs of the tongue to wrap around the shank and the terminal has the characteristics of securely grippin a male terminal which previously has been associated with ring-tongue terminals. It is thus seen that the terminal 2 may be appliedto a male terminal in the same manner as a standard spade-tongue terminal its segments 22 wrapped around shank [8, they are contacted over a considerable portion of their area by the clamping surfaces of the male terminal. Note also that the shank I8 is held near the bottom .of the slot J2, thus insuring that the thus increased area of contact provided between the two terminals is maintained substantially constant; i V

After terminal 2 is clamped in position on a male terminal and ruflles M are flattened, these ruffles tend to return toward their original shape due'to their residual elasticity, and therefore, they exert pressures upwardly onto head 26 of the screw. Terminal 2 is'illustratively made of copper 'and'the cold'working hardens it and tends to raise its elasticlimit with the result that the portions of the legs which previously formed rufiles I4 are relatively hard and elastic thus giving beneficial results. The use of spade-legs made of spring metal such as beryllium copper would augment this upward pressure as well as provide other advantages. For some applications a combination of a rigid fiat spade-tongue with one or more attached spring members having edge rufiles might be employed. Referring to Figure 3, the compressed ruffles Ha create the upward forces on a line 30 which is at the righthand side of shank l 8, and therefore, these forces tend to cock or tip the screw. This advantageous location of the edge rufiles thus gives a locking effect as a screw thus tipped does not loosen easily, while maintainin constant contact pressure.

With this embodiment of the invention, the arrangement is such that when the edge ruflies M are flattened the mouth of slot I2 is closed sufficiently to hold shank l8 in the slot; however, under some circumstances it is desirable to close the slot more or less than is here shown. For example, the wrapping action may be only enough to slightly close the mouth of the slot thus enabling terminal 2 to be removed from the shank I8 by releasing the clamping pressure and exerting a firm pull; the resiliency of legs 8 is sufiicient to permit repeated removal in this manner and reattachment to shank I8. Under some circumstances the mouth of slot I2 is substantially closed causing segment 22 to swing into abutting relationship. These variations in the amount of wrapping are effected by changing the relative sizes and shapes of the base portions 5 and end segments 22 of the spade legs 8 and by varying the shape, size, and number of edge ruifles [4.

The use of more than one ruffie on a given spade leg, besides enabling more complete enclosure of the male terminal, is advantageous when a terminal tongue which was generally flatter prior to its being clamped by means associated with a male terminal is desired. For a given amount of wrapping, the wrapping effect of two rufiies on a given spade leg could be made equal to or greater than that of one ruflle of comparatively larger size. If two such rufiies are used on a given spade leg, the ruille disposed nearest the opening of the spade-tongue might not be easily located sufficiently under the clamping means of a male terminal to be properly clamped thereunder. However, the other rufile on said leg could be of a greater height so that its initial wrapping effect would bring the second, smaller ruffle properly under said clamping means, after which further clamping completes the wrapping by flattening both ruffies simultaneously.

The terminal of Figures 1 to 5 may be manufactured in strip form as indicated at 32 in Figure 6, and when the terminals are applied each is cut from the strip with there being a discarded portion 34 between each terminal and the next.

In the embodiment of Figures 7 and 8 a rectangular spade-tongue terminal 2b is provided which has longer end segments 22b in order that they, 22b, move very close to each other when the rufiles I4 are flattened.

I claim:

An electrical connector construction having a tongue embodying a pair of adjacent spade portions, the inner edge of one spade portion being substantially parallel to the inner edge of the other spade portion and said edges defining therebetween a substantially parallel-sided slot-like recess of greater length than width, said spade portions including a nonplanar rufllle-like formation on their respective outer edges, and said nonplanar formations having a line of bend extending across each spade portion to a point adjacent the inner edge thereof, nearer the inner end of said recess than the distance between said edges but further from the inner end of said recess than one-half said distance.

QUENTIN BERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 955,747 Barcy Apr. 19, 1910 1,026,653 Brunt May 21, 1912 1,703,325 Smarr Feb. 26, 1929 1,978,115 Roper g Oct. 23, 1934 

